Electrical connector with resilient gripping means



5 H. T. THUNANDER ET AL 2,358,515

ELECTRICAL CONNECTOR WITH RESILIENT GRIPPING MEANS Filed Aug. 12, 1954 INV ENTORS HANS -,T- THUNANDER CALVIN J.HOLTKAMP BY m;

5 (l/Ld ATTORNEY United States Patent O ELECTRICAL CONNECTOR WITH RESILIENT GlRlPPING MEANS Hans T. Thunander and Calvin J. Holtkamp, Mansfield, Ohio, assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Application August 12, 1954, Serial No. 449,297

8 Claims. (Cl. 339-17) 'This invention relates to an electrical connector and particularly to a connector for making electrical connections to one or more electrically conducting surfaces on one or more'faces of an insulating support, such as a plate. These conducting surfaces may be on terminal members fastened to the insulating support or they may take the form of printed or deposited surfaces on the insulating support.

1 In the printed circuit art, it is a well known expedient to make detachable electrical connections by providing a connector which will slip over the edge of a flat insulating plate on which various printed circuitsare formed. On the plate, a plurality of separate parallel conducting surfaces or strips extend up to one edge of the plate, and this edge portion of the plate is used as a connector member. The cooperating connector has a plurality of contact surfaces to engage the conducting strips on the plate and is provided with means for attaching it to the edge portion of the plate. Suitable means must also be provided in the connector to resiliently bias each of the contact surfaces into engagement with one of the conducting strips on the plate.

It is an object of this invention to provide a simple, inexpensive type of connector for making electrical connections to one or more electrically conducting strips on one or more faces of an insulating support or plate.

It is another object of this invention to provide an electrical connector of this type in which a minimum number of parts are used and in which all electrically conducting members may be secured manually without the need of any tools.

It is a still further object of this invention to provide an electrical connector of this type in which the ends of the wires fastened to said connector form electrical contact surfaces.

Another object of this invention is to provide an electrical connector of this type in which the contact biasing force is provided by simple inexpensive means.

In accordance with this invention, one of a pair of cooperating. electrical connectors comprises an insulating support for anchoring bared end portions of a plurality of insulated wires to form electrical contacts. Located between the bared wire portions and the support is a resilient insulating member to provide a contact biasing force when the latter is compressed by the engagement of the contacts'in the cooperating connectors.

These and other objects are effected by the invention as will be apparent from the following description taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig-,1 is a perspective view showing the'one end of an insulating plate having a plurality of conducting terminals thereon and a cooperating connector removed from said plate andpartially cut away;

,Fig. 2 is a perspective view of the under side of the terminal plate shown in Fig. 1;

Fig. 3 is.a perspective view showing the under side of the connector shown in Fig. 1;

2,858,515 Patented Oct. 28, 1958 ice Fig. 4 is a front elevation of the connector shown in Fig. 1 with the plate shown in section and engaged with the connector;

Fig. 5 is a section taken along the line VV of Fig. 4 with the electrical conductors shown in full view;-

Fig. 6 is a plan view of the connector insulating block shown in Fig. 1 stripped of all parts except its support;

Fig. 7 is a front elevation of the connector insulating block shown in Fig. 1 stripped of all its parts;

Fig. 8 is a sectional view generally similar to Fig. 5 but showing a second embodiment of this invention; and

Fig. 9 is a perspective view of-a connector generally similar to that shown in Fig. 1 but incorporating a third embodiment of this invention.

Fig. 1 shows a connector assembly 10 comprising an insulating support such as a plate 11 having on one face thereof a plurality of terminal members 12 extending parallel to each other and substantially normal to an edge 13 of said plate. A novel cooperating connector assembly 14 has a channel 15 to receive the edge of the plate 11 and the terminal members 12 thereon to make electrical connections thereto from bared metal ends 17 of separate insulated wires 18 which form a cable terminating in the connector 14. l

The terminal members 12 have portions lying along the upper surface of the plate 11 to form electrical contact surfaces to engage the wire end portions 17 in the connector 14. One end of the terminal member 12 is bent over the edge 13 of the plate 11 and the other end extends through a hole in the plate 11 and therebeneath to form a depending terminal portion 16. Wires 19 from circuit assemblies on the plate may be soldered to the terminal portions 16 as seen in Fig. 2. The details of the plate 11 and terminal members 12 are the subject matter of a copending application of C. J. Holtkamp, Serial No. 472,5 82, filed December 2, 1954 and assigned to the present assignee. This invention, however, is equally applicable for use with printed circuit assemblies having printed or deposited conducting coatings forming contacting surfaces on one or more faces of an insulting plate near one edge thereof. g V

The connector 14 shown in Fig. 1 comprises a support for the ends of the wires 18, such as an insulating block 20 having the channel 15 therein to receive the edge of the board 11. The channel 15 is bounded on three sides by opposed walls 21 and 22 and a third wall 23 extending therebetween. The insulated wires 18 extend into fixed wire guiding or retaining means comprising passages 24- in the third wall 23 of the insulating block, and the bare end portions 17 of these wires extend therefrom into the channel 15. Within the channel 15 the bare wire ends 17 have an electrical contact forming portion passing over a face of a resilient insulating body or member comprising a relatively flat strip 25 positioned against a supporting surface formed by the flat under side of the upper wall 22. The strip 25 is preferably made of a heat resistant silicone rubber material. Other resilient insulating materials could be used but silicone rubber is preferred in this application because its resiliency varies little with temperature, it is very slow aging at elevated temperatures, and it contains no sulphur which can badly tarnish contact surfaces. The surface of the strip 25 should be sufficiently hard and abrasion resistant to prevent the wires 17 from cutting it.

The separate wire end portions 17 are bent around the edge of the upper wall 22 in interlocking relationship therewith as seen most clearly in Fig. 5. The upper wall 22 is provided with fixed wire retaining means comprising a serrated edge having a series of tapered notches 26 to receive and hold the hooked end portions 17 of the wires uniform spacing therebetween and prevent lateral movement, but are also of such a taper and such width that the end portion of the Wire is pinched when the wire is pulled back into the notch. If the wire should happen to be pulled from the cable end, its end portion will be pinched still more tightly and it is normally not possible to pull the Wire out of the connector block. The wire end portions 17, being held against the face of the strip 25 and independently retained at opposite ends of the contact forming portion thereof by the passages 24 and the notches 26, located along opposite sides of the strip 25, retain the strip 25 within the channel when the edge of the plate is removed from the channel.

The lower wall 21 of the connector shown in Figs. 1 and 3 forms a holding or gripping member attached to the insulating wall 22 and cooperating therewith to support or hold the electrical contacts on the insulating plate 11in firm engagement with the wire contact portions. The latter extend over the resilient insulating strip and are biased thereby toward the wall 21 when the connectors are engaged. Although the lower wall 21 of the connector is shown as an integral part of the insulated block 20, it may take the form of any insulating support which is held fixed opposite the upper wall 22 of the block to form a plate receiving space therebetween.

The passages 24 extending through one wall of the insulating block have a substantially circular cross section adjacent the outside of the block. The inner ends of these passages adjacent the channel 15 have a reduced cross section in order to prevent the insulation on the wires from extending through the passages and into the channel. The inner ends of the passages have an elongated cross section as shown in Fig. 7 with the dimension along the direction of the channel being reduced, and the dimension along a line normal to the opposed walls 21 and 22 being substantially the same as the diameter of the outer portions of the passages having a circular cross section. The reduced channel ends of the passages 24 restrict lateral movement of the bare wires extending therethrou'gh but allow them some freedom up and down, permitting them to be more easily deflected when the edge of the insulating plate 11 with its associated contact members 12 is inserted in the channel as shown in Figs. 4'and 5.

The tapered notches 26 and the ends of the wires 17 extending along the upper face of the wall 22 of the insulating block are separated by raised parallel ribs 27 formed integrally with the block and extending from the front'notched edge to the rear edge of the wall 22.

An insulating cover plate 31 is attached to the upper wall of the insulating 27 and the spaces therebetween to prevent accidental contact with the 'wire and portions 17 and also to help keep the wire end portions -in a relatively fiat position against the upper surface of the wall 22. The cover helps to keep the end portions of the wire hooked around the notched edge of the wall 22 to prevent withdrawal of the wire from the connector block when a force tending to pull the Wires out of the passages 24 is applied thereto.

The upper wall of the insulating block is provided with cover retaining means comprising raised portions near its ends. These raised portions-30 are provided with grooves 32 therein generally parallel to the ribs 27 to receive'the ends of the cover. The cover is retained in the grooves by the upstanding stop 33 on the front center of the upper wall 22 and by the upper end of an L-shaped supporting bracket'34 fastened to the rear wall 23 of the insulating block. The cover 31 has a notch 35 to receive the stop 33 and is sufficiently flexible so that it may be bowed'to raise its center portion above the stop and permitit to be slid out of the grooves 32 without removing the bracket 34 from the insulating block.

The supporting bracket 34 is attached to the insulating block 20 by a single screw. The outside face of the wall 23 is provided with two vertically disposed ribs 36 on block 20 and extends over the ribs opposite sides of the supporting bracket 34 to prevent the latter from rotating with respect to the block 20.

The supporting bracket 34 may be attached to any suitable base and the connector 10 may be provided with suitable supporting means to prevent its relative movement with respect to the connector 14 when engaged therewith.

Extending between the opposed walls 21 and 22 near the center of the insulating block is a barrier 40 separating the channel into two portions. The barrier not only adds strength to the insulating block but also serves as a guiding means which cooperates with the slot 41 formed in the edge 13 of the plate 11 to insure that the terminals 12 will be accurately aligned with the bared wires 17 when the plate and the connector are engaged.

The resilient insulating strip 25 functions to bias the bared wires 17 with a spring-like action into engagement with the terminals 12 on the plate 11 when the latter is forced into the channel 15. The total thickness of the plate 11 and the terminals 12 thereon is greater than the space between the bared wire ends and the upper face of the lower wall 21 of the insulating block 20. Therefore, when the plate is forced into the channel, the Wires 17 will be forced against the resilient insulating strip 25 and the latter, being slightly compressed between the wires 17 and the wall 22 by the stresses so imposed, will maintain sufficient pressure for good electrical contact between the wires 17 andthe terminals 12.

FIG. 8

In a second embodiment of this invention shown in Fig. 8, a modified connector engages an insulating plate 51 in a manner generally similar to that of the first embodiment shown in Figs. 4 and 5. However, the lower half of the connector 50 is substantially an inverted duplicate of the upper portion of both this connector 50 and the connector 14, thus permitting this connector to be used for making electrical connections on opposite faces of the plate 51. The conducting terminals on the plate 51 are shown as thin printed or deposited conducting coatings 52 on opposite faces thereof extending near the edge 53 of the plate 51. Some parts of this second embodiment corresponding to similar parts of the first embodiment are identified by numerals with a prime notation.

A resilient insulating strip 25' is provided adjacent each of the opposed walls 21 and 22', and both of these walls are provided with tapered notches 26', ribs 27 and covers 31 and guiding means 40 in the same manner as is the upper Wall of the connector 14 shown in the other figures. Stops 33' are provided at the front of the block to retain both covers 31, the latter being retained at the rear of the block by the supporting bracket 34'.

The third wall 23' of the connector of Fig. 8 has two vertically separated sets of passageways 24' therethrough to permit the ends of the wires 18' to extend into the channel on opposite sides of the insulating board 51.

In the embodiment shown in Fig. 8, the insulating board51 will force the upper and lower sets of the wire end portions 17 apart when it is inserted into the connector 50. Both of the resilient insulating strips 25' will be slightly compressed against the walls 21' and 22' and good electrical contact will be maintained between the wires 17 and the conducting coatings 52 on the board 51.

FIG; 9

A third embodiment of this invention is shown in Fig. 9. The insulating connector block is identical to that shown in Fig. 1 except for the provision on the upper face of the wall 22 of wire retaining means comprising a plurality of studs for more securely anchoring the ends of the wires 17. One stud is located in each groove 61 between the raised ribs 27 on the upper wall. The end portion of the wire 17 which extends means from the tapered notch 26 is wrapped around the stud 60 to prevent the wire from slipping when stresses are applied to the portions of the wires outside of the connector.

Assembly forcing them to the position shown in Fig. 5 with they fingers. This invention may be readily applied to a connector in which only one electrical connection is made rather than a plurality of connections as indicated in the drawings.

Although this invention is illustrated in a connector for attachment to a flat plate having electrical contacts thereon, other shapes of cooperating connectors may incorporate this invention.

While the invention has been shown in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What is claimed is: g

1. An electrical connector comprising an insulating wall having a supporting surface, a resilient insulating member adjacent said surface, wire retaining means fixed With respect to said plurality of separate wires each, and a surface on opposite sides of said resilient member having an electrical contact forming portion which extends over said resilient member, each wire being independently held at the opposite ends of said portion by said wire retaining means, said wire retaining means including at one side of said member a separate passage for each of said wires, said resilient member being so located as to provide a contact biasing force by being compressed between said supporting surface and said wire contact forming portions when the latter are engaged by contact surfaces on a cooperating connector.

2. An electrical connector comprising an insulating wall, gripping means attached to said wall and having a portion spaced from said wall to form a connector receiving space therebetween, a resilient insulating member in said space adjacent said wall, wire retaining means fixed with respect to said wall, and a plurality of separate wires each having an electrical contact forming portion extending over said resilient member on the side opposite said Wall, each Wire extending through a passage in said retaining means at one end of said portion, said wire interlocking with said retaining means at the other end of said portion to hold said portion against said member, said resilient member providing a contact biasing force in the direction toward said portion of the gripping means when a cooperating connector is received in said space.

3. An electrical connector comprising an insulating block having a pair of opposed parallel walls and a third wall joining said pair of walls, said walls bounding a channel in said block, one of said pair of walls having an edge with a plurality of notches therein spaced from said third wall, said third Wall having a plurality of passages therethrough communicating with said channel, a resilient insulating strip within said channel adjacent said one wall, and a plurality of electrical conductors, each of said conductors extending through a different one of said passages into said channel on the side of said strip opposite said one wall and being bent near its outer end and extending through one of said notches, said strip being retained against said one wall by said conductors.

4. An electrical connector comprising an insulating sup- 6. port having a supporting surface, a resilientinsulating member adjacent said surface, a plurality of wire retaining means fixed with respect to said surface, an insulated wire having a bared electrical contact forming portion extending over said resilient member and held at the opposite ends of said portion by said wire retaining means, one of said wire retaining means comprising a passage in said support through which said wire extends, said passage having a reduced cross-section at a point within said support permitting said bared wire portion to pass therethrough but preventing an insulated portion of said wire from passing therethrough, said resilient member being so located as to provide a contact biasing force by being compressed between said supporting surface and said contact forming portion when the latter is engaged by a contact surface on a cooperating connector.

5. A pair of cooperating electrical connectors including a connector comprising an insulating support, a resilient insulating body adjacent one side of said support, wire retaining means fixed with respect to said support, a pluraltiy of separate wires each having an electrical contact forming portion extending over said resilient body on the side opposite said support, each wire being independently held at the opposite ends of said portion by said wire retaining means, said wire retaining means including a separate passage for each of said wires, a second connector comprising a second insulating support, a plurality of electrical contacts carried by said second support, and a holding member connected to one of said supports, said holding member being positioned to hold said electrical contacts in engagement with the contact forming portions of said wires and said resilient body biasing said wires into engagement with said contacts when said connectors are engaged.

6. A pair of cooperating electrical connectors comprising a first connector having an insulating block in cluding a pair of opposed parallel Walls and a third wall joining said pair of walls, said walls bounding a channel in said block, one of said pair of walls having an edge with a plurality of notches therein spaced from said third wall, said one Wall having a plurality of ribs on the side opposite said channel, each rib lying between two of said notches, said third wall having a plurality of passages therethrough communicating with said channel, a resilient insulating strip within said channel adjacent said one Wall, a plurality of electrical conductors each having an end portion extending through a different one of said pass-ages into said channel on the side of said strip opposite said one wall and bent to extend through one of said notches, said ribs electrically isolating the ends of said conductors, an insulating cover overlying said ribs on the outside of said one wall, retaining means attached to said block for securing said cover in place, a second connector comprising a flat plate having a plurality of electrical conducting surfaces on at least one side thereof adjacent an edge of said plate, the edge of said plate being movable into said channel with said one side of said plate adjacent said resilient strip, the thickness of said plate and the conductor thereon being suflicient to compress said strip so that the conductors in said block will be engaged in good electrical contact with said surfaces, and interengaging means on each of said connectors for guiding them into proper alignment with each other.

7. An insulating block for an electrical connector comprising a first insulating wall having a plurality of notches in one edge thereof, a second insulating wall integral with said first wall in generally parallel spaced relation to said edge and having a plurality of passages therethrough, and a gripping member integral with one of said walls and having a portion extending opposite said first wall to form a connector receiving space therebetween, said first wall having a surface facing said gripping member and extending between said edge and the 7 second wall opposite at least two of said notches and twoof said passages.

8. -An insulating block for an electrical connectorrcotnprising a first insulating wall having a plurality of notches in one edge extending therethrough to opposite faces of the wall, a second insulating wall integral with said first wall in generally parallel spaced relation to said edge and having a plurality of passages therethrough, a holding member integral with one of said walls and having a portion extending opposite said first wall to form a 10 connector receiving space therebetween, and a plurality of raised ribs extending between said notches and from said edge on the side of said first wall remote from said holding member.

Kralnrn, A. pages 152-154.

Lager Aug. 30, .1949 Rickabaugh Sept. 16, 1952 Johanson June 9, 1953 Ericsson et al. Dec. 29, 1953 Hammerly Feb. 16, 1954 OTHER REFERENCES 1.: Electrical Manufacturing, June 1953,

UNITED STATES PATENT OFFIICE CERTIFICATE OF CORRIEQTIODI Patent No. 2,858,515 October 28, 1958 Hans T, Thunander et al,

It is herebfi certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 35, after "said" insert surface on opposite sides of said resilient member, and a lines 35 and 36 strike out and a surface on opposite sides of said resilient member".

Signed and sealed this 30th day of June 1959 (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents Attesting Oflicer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,858,515 October 28, 1958 Hans T, Thunander et al.,

It is hereby; certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5 line 35, after "said" insert -=surfaoe on opposite sides of said resilient member, and 21 lines 35 and 36, strike out and a surface on opposite sides of said resilient member".

Signed and sealed this 30th day of June 1959 (SEAL) Attest:

KARL H. MINE Attesting Officer ROBERT C. WATSON Commissioner of Patents 

